XG—SZLY综合录井仪气测部分技术特点

为了在气测录井中获得真实的地层含气饱和度值,提高自动采集样品的质量,同时解决好因分析周期长或仪器故障而漏测薄油气层等难题,通过技术工艺创新,使气测仪制造更适应现场的需要。该重点介绍了XG-SZLY综合录井仪气测部分采用自动真空蒸馏定量脱气器、钻井液恒流定体积脱气器、钻井液长引流装置的技术特点以及数据采集、处理全过程的自动化等,这些新技术的采用较好地解决了上述难题。另外,还简介了与该仪器配套的定量荧光分析和卫星数据双向传输系统。     

自动真空蒸馏脱气器AVMS和电动脱气器效果比较

为了获得钻井液中真实的地层含气量,XG-QY2气测仪中加入了自动真空蒸馏脱气器,以此来实现上述目标,将井口刚返出的钻井液通过引流装置引入仪器房,定时定量进行“全脱”分析,为了验证其脱气效果,用性能指标完全相同的分析器A和B分别分析自动真空蒸馏脱气器(AVMS)的样品气和电动脱气器脱出的样品气,试验证实,AVMS提供的样品气中烃组分齐全,C4~C5峰明显;总烃含量比电动脱气器脱出气体含量高出10倍以上,脱气效果好,替代传统的电动脱气器进行气测井,有利于提高油气勘探精度。     

XG-QY2新型气测仪简介

将钻井液引入录井房,并行地通过恒流脱气器和自动真空蒸馏脱气器AVMS,脱出的样品气分别进入分析器A和B实行多道组合分析。其特点是:分析周期短,AVMS以4min为一周期参与实时录井。这样,有利于现场早期、快速发现和评价油气层,并使漏测几率降到最小。     

脱气器的现状及发展趋势探讨

气测录井数据精确与否,一方面取决于气体分析仪器的精度,另一方面取决于气体采集仪器的效率。文章针对脱气器的发展,探讨了不同时期所应用的脱气器的优缺点以及存在的问题,在此基础上,通过对比分析,提出了今后脱气器的发展趋势,即发展真正意义上的定量气体脱气器应作为今后开发研制的主攻方向。     

钻井液定量气测分析系统设计与应用

钻井液所携天然气组分的定量采样检测是气测录井的难题,也是录井技术的发展方向之一。结合上海神开石油科技有限公司对定量气测分析系统的开发与应用,验证了全新的定量脱气器和色谱仪。定量脱气器通过PLC流量反馈控制技术实现了钻井液的定量采样脱气,其钻井液处理量可以与常规脱气器相当,脱气筒的加热设计进一步提高了对天然气高沸点组分的测量准确性,定量脱气器的模块化设计更便于现场安装和搬运;与之配套的色谱仪采用EPC流路控制技术和双色谱柱设计,可以实现对C_1-C_8组分的快速分离检测,C_(6+)组分的在线测量则进一步拓展了现场气测录井的应用范围。     

膜分离技术在气测录井中的应用研究

传统的气测录井存在脱气效率低、脱气过程不稳定等问题,一直是困扰实时准确分析钻井液烃类气体含量的瓶颈,直接影响油气评价的准确性。利用膜分离技术,能高效、稳定地脱出烃类气体,实现了真正意义上的定量脱气。设计的脱气器可直接插入钻井液中提取分析成分。渗透膜脱气技术突破了传统气测录井的气体采集方式,可提升气测录井水平,提高油气评价准确性,有助于油气储层的发现。实现了不同钻井条件下对不同钻井液系统内气体的定量检测分析。     

影响气测录井发现和准确评价油气层的因素分析

以通过钻井液实时连续检测烃类气体为目的的气测录井在油气勘探开发过程中一直起着其它录井手段无法替代的作用,该通过对气测录井检测分析手段以及钻井过程中一些尚不可控条件的分析,阐述了影响气测录井发现和评价油气层准确性的几个方面的主要因素,分别为钻井工程,脱气器、仪器标定及取值方式权及气测后效对气测录井的影响,结合因素分析,探讨了消除部分影响因素的方法。为加强气测录井技术深入研究,使其真正实现从定性向定量发展,提出了主攻方向。     

影响气测录井发现和准确评价油气层的因素分析

以通过钻井液实时连续检测烃类气体为目的的气测录井在油气勘探开发过程中一直起着其它录井手段无法替代的作用。该文通过对气测录井检测分析手段以及钻井过程中一些尚不可控条件的分析,阐述了影响气测录井发现和评价油气层准确性的几个方面的主要因素,分别为钻井工程、脱气器、仪器标定及取值方式以及气测后效对气测录井的影响,结合因素分析,探讨了消除部分影响因素的方法。为加强气测录井技术深入研究,使其真正实现从定性向定量发展,提出了主攻方向。     

自适应液位电动脱气器的研制与应用

脱气器处于气测录井最前端,固定安装在钻井液出口缓冲罐上,是气测录井作业关键设备之一,脱气器的脱气效率直接影响到录井气测资料采集的稳定性、准确性和连续性,进而影响油气显示发现和评价效果,并且脱气器的安全性直接影响到操作人员人身安全。通过分析传统脱气器结构设计存在的局限,借鉴自动化控制技术、磁性感应技术、阿基米德浮力原理,研制出一款符合国际安全供电、防堵、自适应液位的全新电动脱气器,实现了脱气器自动化运转及安全供电,降低了人工劳动强度,消除了安全隐患,节约了维修成本,有利于提高气测录井资料的稳定性、准确性和连续性,具有较好的推广应用前景。     

GC-Tracer半透膜多组分气体检测系统

在气测录井中,传统的搅拌式电动脱气器存在体积大、影响因素多、脱气不定量等问题,传统气测录井存在检测组分少导致信息不充足等缺点。针对上述问题威德福公司研发的GC-Tracer半透膜多组分气体检测系统,采用半透膜脱气器代替传统搅拌式电动脱气器,具有体积小、安装灵活、脱气效率稳定、受外界干扰小等优点;多组分气体检测系统可在60s内实现C_1-C_8、苯和甲苯、二氧化碳的检测,大幅增加了地层检测信息量。现场应用结果表明,以定量脱气及多组分气体检测为基础,可准确发现油气层,快速精确评价地层含油气信息,能更好地服务于勘探开发,在深海录井、非常规录井、欠平衡录井、混油钻井液录井等方面具有很好的应用前景。     

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利用陕甘宁盆地中部气田气井的系统试井资料，在建立气井二项式产能方程系数（Ｂ）与其绝对无阻流易量之间关系的前提下，提出了利用单点测试资料建立气井产能方程，确定气井绝对无阻流量的新方法，该方法较以往文献介绍的方法有较大的优越性，它不依赖于一个气田气井的ａ统计值，对单点测试条件亦没有限制，利用单点测试资料能同时能建立气井的产能方程，确定气井的绝对无阻流量。     

Improved material balance equation (MBE) for gas-condensate reservoirs considering significant water vaporization

The phenomenon of retrograde condensation occurs when the reservoir pressure declines below the dew-point pressure causing gas condensation and developing two-phase flow. Material balance equation (MBE) of gas condensate reservoirs is a real challenge because of the change in fluid composition and complexity of phase behavior.Neglecting the effect of water vaporization may lead to inaccurate predictions of the material balance equation. Therefore, the main objective of this study is to develop an improved MBE model capable to describe gas condensate reservoirs under significant vaporization of connate water and water influx driving mechanism.A new parameter is developed to consider water vaporization. This parameter is used to derive equations for gas condensate reservoirs considering vaporization effect with and without consideration of water influx. Numerical examples have been developed and used to compare the accuracy of the newly-developed model with conventional ones using actual reservoir depletion and production data.The results indicated that water vaporization has an important effect and should be considered for accurate MBE predictions. Error analysis showed that the newly-developed equations are more accurate than previously-developed models. The accuracy of the new MBE is attributed to the additional parameter introduced considering high pressure and high temperature conditions.The application of the new material balance equation will have important impact on predictions of initial gas in place, reserve calculation and future simulation studies.     

确定气井高速湍流系数的新相关经验公式

在井底附近地带，对于高速气体的流动，湍流或非达西流动的产生是不可避免的。湍流不公增加了表皮系数，而且降低了气井的产能。新的确定气井高速湍流系数的相关经验公式，较以前文献的相关经验公式，具有更好的代表性，可以用于确定不同渗透率储层的高速湍流系数和非达西流动常数。     

Comprehensive investigation and evaluation for the different multiphase flow correlations in gas wells

Gas production represents an important source of energy used in different industries. Accurate production forecast of gas wells helps in decision making and maximizing reserves.Petroleum engineers model existing conditions of the fluid flow to help them in predicting wells’ future performance. The modeling of single-phase flow is considered the simplest case, but considering multiphase flow (oil, gas, and water) makes it more challenging.We studied and evaluated the different multiphase flow correlations using two commercial software (A and B). A database of 537 bottom hole flowing pressure data points was used which covered 33 different flowing, well geometry, and tubing diameter conditions. 14 correlations were used from Software “A” and 26 correlations were used from Software “B” to calculate the pressure drop in the tubing for each case. The target was to determine the best correlation(s) for each case and establish guidelines to help petroleum engineers in selecting the best correlation when actual bottom-hole flowing pressure data is unavailable. We could determine the expected average percent error (APE) and average absolute percent error (AAPE) for each correlation for different flow conditions. Also, for different conditions, we calculated the different statistical parameters for the calculated pressure from each correlation including normalized root mean square error (NRMSE), coefficient of determination (R²), and the standard deviation (STD). We also created a map to show which software will give the lowest error for the different flow and well parameters. Then, a validation database was used to confirm the previously determined results using a new set of data. The results were validated with a percentage of 91% for Software “A” and 89% for Software “B”.For both software programs, Gray’s correlation was found to be the best correlation for the entire database. It gives AAPE of 5.73% and 9.72% for software A and B, respectively.This paper will help petroleum engineers select the best multiphase flow correlation(s) in different flow and well conditions. Also, it will give them guidance for the critical conditions which give a wide range of the calculated pressure drop using the different multiphase flow correlations.     

求取压裂后气井产能的椭圆流方法

气井的绝对无阻流量是确定气井产量的主要指标。通常在确定压裂后气井的产能从而求取无阻流量时，采用近似的流动模式来表征压裂后流体渗流规律的变化，而没有考虑其真实流动形态。文章根据气藏的渗流机理，对于有对称双翼人工裂缝的均质等厚气藏，地层中的真实渗流情形是拟径向非达西渗流，流动等势线为以井眼为中心的椭圆族，流线为垂直椭圆族的放射线。根据椭圆族的特征与渗流规律，从广义的达西定律出发，可推导出裂缝区域外椭圆族内的流动公式。而对于c椭圆内区域的渗流，由于存在两种渗流介质，认为压裂裂缝内和垂直裂缝附近区域的流动为非达西单向渗流，从而推导出裂缝区域附近的流动公式。综合裂缝区域内外的渗流，可以推导出稳态情况下的气藏产能公式，根据该公式便可求取无阻流量，其中c可根据协调条件求出，给出的计算实例结果与试井数据相吻合。     

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在气井的各类腐蚀中，冲蚀的危害性极大。分析了冲蚀产生的原因及影响因素，提出了随着流速增加，冲蚀加剧，如果气流速度增加３．７倍，则腐蚀速度增加５倍。提出计算流速的公式及考虑其它影响因素时的校正方法，利用该方法所绘制的图版在仅知道气井井口流动压力与油管内径的情况下内径的飞速２下便可判断气井有无明显的冲蚀情况，便于现场应用。     

A new plotting technique for modeling critical flow through Multi-Orifice wellhead chokes

Well production rate is one of the most crucial parameters for reservoir modeling, management and surveillance. In most cases, this parameter is known by using empirical correlations to estimate the flow rate passing through fixed wellhead choke. However, in offshore and hostile environments, the multi orifice valve (MOV) choke is installed as a substitute to control the well production remotely. Due to complexity of flow in this type of restriction, theoretical choke modeling is impossible and the available empirical correlations for fixed chokes can’t be used for rate calculation. In this paper, a new, yet simple plotting technique is proposed for modeling the flow of gas condensate type fluid in MOV wellhead choke to estimate well gas rate. By using a set of test separator data including 164 well rate, choke opening and wellhead flowing pressure, gathered from an offshore gas condensate reservoir located in Middle East, the technique was developed and validated. The results revealed that proposed methodology can estimate well rate with an absolute average percent deviation of 5%. The critical need for rate data, make the findings of this paper attractive for petroleum industry.     

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新疆温吉桑地区温八块凝析气藏属低孔、低渗,非均质性较严重气藏,试井测试资料较少,常规的产能确定方法（如利用试井资料确定产能方程,采气指数法或一点法）应用较困难。文章从气井渗流理论出发,以二项式产能方程为基础,对气井渗流方程进行了分析研究,结合温吉桑温块凝析气藏具体情况,提出新的气井产能确定方法－单位平方地层压力无阻流量法及单位地层系数采气指数法,并进行了实例计算,最后结合气井连续排液条件和数值模拟     

利用气井压力恢复资料求产能方程和排泄半径

气井的产能方程是求取气井无阻流量的重要方程,通常由系统试井获得。对于低渗透气藏,用常规的系统试井方法确定二项式产能方程往往比较困难。从不稳定渗流理论出发,得出了利用压力恢复资料求气井二项式产能方程的方法,由该方程还可以计算气井的排泄半径。经实例分析,本方法可行、有效。     

无测试资料条件下气井合理产能优化研究

在气藏开发方案设计中,气井合理产能是气藏经济开采的重要决策依据。垦东34块馆上段气顶油藏位于胜利油气区极浅海海域,矿场无稳定试井资料。为确定气井合理产能,采用经济极限初始产量、临界携液产量、绝对无阻流量和数值模拟方法进行了优化研究。研究结果表明,气井合理产能控制在1.5×104m3/d时,可实现气井在不出砂条件下长期稳产,并可提高气顶油藏开发效果。投产后气井生产效果理想,从而为无稳定试井资料条件下确定气井合理产能提供了一套操作性较强的研究方法。